Any way you slice it, $287, 273 is a lot of money, especially in this economy. For one-term SenatorClaire McCaskill, D-Mo., up for re-election in 2012, that’s the amount of personal property taxes she failed to pay since 2007 on a plane she and her husband, a millionaire businessman, partially owned.

“I have discovered that the…personal property taxes on the plane have not been paid,” McCaskill told a small number of reporters on a conference call Monday. “There should have been a reporting to the county of the existence of this airplane…There are people I could blame for this, but I know better. As (a former) auditor, I know I should have checked for myself. I take full responsibility for the mistake.” Audio of the call was sent to Fox by a McCaskill aide and can be found here.

The senator said she had done her own “thorough review” of all 89 flights she had taken following a political controversy that erupted recently over the same plane that was first reported by Politico.

The senator had used the plane for political purposes paying for the travel with taxpayer money from her Senate office, a “mistake,” the senator said, for which she reimbursed the government nearly $89,000. “All of the money has been repaid for the public funds,” McCaskill said Monday.

The senator said she had paid sales taxes on the plane, both local and state, evidence, she said, that she had made no attempt to duck her financial responsibility. “I want to reiterate, there was no attempt to evade the plane…This is just a mistake that I take full responsibility for.”

But Republicans did not buy the explanation from McCaskill, a top GOP target in 2012. “In the past two weeks, we have learned that Claire McCaskill billed taxpayers for political travel and failed to pay nearly $300,000 in personal property taxes on her plane. Over the last four years, cash-strapped school districts and the children in these schools have been deprived of these much-need funds,” MissouriRepublican Party chairman David Cole blasted in a statement from his office.

One senior GOP strategist with experience in Missouri politics criticized, “While numerous cities across her state struggle to pay police, firefighters, teachers, some even getting laid off, Claire McCaskill is using that money to fly around willy nilly. That money would pay for six teachers to do their job for a year.” (According to the Missouri Economic Research and Information Center, that is correct – an average teacher salary from 2009-2010 was $45,317.)

McCaskill recently co-sponsored a bill in the Senate that would send pink slips to federal employees who are found to have unpaid taxes, a measure Republicans also highlighted Monday, calling the Democrat a hypocrite. But a McCaskill aide said that was not a fair attack. “Those are people who knowingly have not paid their taxes and have refused to own up to it and to make that right,” an aide told Fox. “She didn’t knowingly do this. This is a situation where a mistake was made. As soon as she found out…she made it right,” the aide told Fox.

Because planes are not licensed the way automobiles are with the state of residence, rather they are licensed with the Federal Aviation Administration (FAA), the state has no record of ownership and, therefore, sends no property tax bill.

As for that bill, the McCaskill aide said, “The senator has already written and sent the check to repay this money. There was no effort to evade taxes here.”

Still, the controversy has proved too much for the senator, who, according to her office, has no plans for public events this week while the Senate is on recess. An audibly exasperated McCaskill told reporters, “I have convinced my husband to sell the damned plane. He has hired a broker, and I never intend to step foot on that plane ever again.”

But with Missouri politics being a rough and tumble sport, the sale of the plane is not likely to put the issue to rest for the senator any time soon.